F800GT Unusable in Hot Weather

[racer7]

Today we had our first 80 degree spring day so we took the new F800GTs out for run- about 120 miles or so.

Both of us had noticed the warm air around the crotch in cooler weather. Not bad at all, even useful sometimes. BUT..

WARNING- the F800GT is a serious crotch roaster in 80 degree weather- to the point a stock one is probably unusable in 90 or 100 degree weather.

The source of the heat is the 2 eyebrow vents in the plastic near the riders knees. Rad heat exits there and is blown directly into the riders crotch for both of us.

This is a rare problem with BMWs- none of our 4 other BMW's directs excess heat on the rider and 2 of them are water cooled K's- a K1200RS and a K1200GT. The F800GT is as bad or worse than some 1980 Hondas I remember.

I am getting really tired of fixing BMW screwups but here is yet another if these bikes are to be summer usable. And it has to be done without creating some other sort of heat problem.

Also, airbox temp control on the F800GT is very poor- data logging shows heat soaking continually raising engine intake air temp while riding- the heat coming from the rad and perhaps the pipes. It is likely to go at least 40 degrees over ambient for intake air temp on a hot day- I got a good part of that on a brief 40 mile highway speed segment today and temps were continuing to climb when logging was stopped. This doesn't impact rider comfort but there is clearly useful free power to be had by getting cold denser air to the motor. Is it too much to expect some basic heat insulation on an airbox?

I would strongly suggest to any of you looking at the F800GT to NOT BUY ONE unless you have done a hot weather demo of at least 20 or 30 miles at highway speed and find the crotch heat level acceptable to you.

When I get around to addressing these issues, I'll post results.

Be nice if BMW did all their homework on new models...I can fix almost anything but this type of very basic goof is inexcusable.

To me this also means that the new watercooled RT is also a no-go unless it passes a hot weather test run (haven't ridden one yet). Folks who don't properly develop one bike can as easily repeat the error with another. HINT- try getting some actual customers to ride development models in hot and cold conditions. The current "professional" crew is missing obvious issues.

 

[jandhumphreyme]

BMW is not the only MFG with this issue. My old Triumph Trophy and SprintST were both roasters in hoter weather. My son in laws current CBR is hot as well.

 

[advenbob]

I have been riding my GT for 13 months now. Living in the Southwest, I am very familiar with high ambient temperatures. Friends of mine have 800ST's and mentioned the heat, but I did not pay too much attention to their comments. Well, I found out pretty quick what they were talking about.
Riding in temps at or above 85 wearing a pair of blue jeans, the heat becomes pretty intense. On touring trips, I wear First Gear over pants and LD comfort shorts. Can still feel the heat, but it is not as intense. July and August are quite warm in Phoenix and last year was no exception. I considered plugging the vent holes in the plastic, but noticing the cylinder head is located just inside the vents, decided against that action. Not sure what unintended problems might occur changing the air flow around the engine. The only fix I current have is just hanging your knee's out in the wind when at speed.
Due to past experience with BMW, I think it is useless to try and talk to them about this issue. I have 3rd degree burns on both legs from my 03 K1200GT that occurred riding home from the Top of the Rockies rally one summer. They said they didn't have any heat problems with the K motor, altho the riding public knows the brick had these issues from the beginning. The worse being those who rode/ride the K1.
If anyone has a credible fix for this issue, I am all ears. This July I will be on the road heading to St. Paul and August will be in the Durango Co. area, away from the 105-110 heat of Arizona.
It is times like these I miss my 07GSA. A couple of years ago, living in Yuma, we had 3 weeks or more with days at 115. Working nights I would ride in to work mid afternoon in those temps and ride home at 2 am or so when it cooled down to 96 or so. No heat issues with the bike.

 

[glenb]

I am sorry to hear this, I feel your pain, I don't do well with heat (but we could use some of that high ambient temp here, about now)

BMW is not the only MFG with this issue. My old Triumph Trophy and SprintST were both roasters in hoter weather. My son in laws current CBR is hot as well.

Yeah, my last two bikes were "hot". A 2003 FJR1300, which I put up with the heat for the ride and performance, and a 2010 Victory Vision 8 Ball, which I just traded for a new F700GS.

The Vision is quite hot in the warm weather, the only saving thing for it is to install the optional lower deflectors which can be turned to bring air onto the rider's legs. I have demo rode the Victory Cross Country and also found it very hot when stopped in traffic.

It seems heat can be quite a problem with various makes/models.

 

[JamesInCA]

Ever ridden a brick? First day with my '87 K75 I rode it 200 miles in SoCal October weather. Second-degree burns on my inner thighs.

 

[racer7]

The only brick I ride is a K1200RS and its fine re heat control- no issues worth noting. Same for my wedge motor 06 K1200GT though it has a bunch of other issues. I am aware that some bricks have a solid rep for frying riders- for which BMW no doubt said something like the German equivalent of no way Jose..

The problem with the F800GT is highly specific and very localized - unique to the model - it is NOT a general "hot air wafting off the rad or motor" issue which has been perennial problem on various bikes ever since the first watercooled bikes became common- the GT does not have that issue. It is restricted to hot air pouring out of 2 eyebrow ducts at speed on warm/hot days and landing in the riders crotch.

Blocking the ducts would fix it in a blink but might fry the engine computer above them, for example. How to improve ducting isn't so obvious but I haven't opened it up (again) for a good look at the guts re heat flow, yet.

Going back to UJMs seems almost silly but (again) I'd note I've got no (heat) issues with my old watercooled Transalp with its two radiators. The heat is effectively ducted out under the rider even though the rads are buried in the bike behind two layers of protection from incoming rocks- but it is a much simpler bike with more space underneath to do that. But it does burn about the same amount of fuel per unit of time so is creating about as much heat to dump.

Glen- I used to live in Williamsville NY and work in Buffalo across the river from you. Have they pulled the boom on Lake Erie to let the ice out yet? (For those not from there- watching that ice go over Niagara is about the only time the locals go to the falls- very good show at its peak but brief. A few million tons of ice makes quite a noise falling that far). I envy your summers up there- now that the lake has come back thanks to pollution controls, the river and lake are gorgeous in the summer for boating and fishing.

 

[glenb]

fGlen- I used to live in Williamsville NY and work in Buffalo across the river from you. Have they pulled the boom on Lake Erie to let the ice out yet? (For those not from there- watching that ice go over Niagara is about the only time the locals go to the falls- very good show at its peak but brief. A few million tons of ice makes quite a noise falling that far). I envy your summers up there- now that the lake has come back thanks to pollution controls, the river and lake are gorgeous in the summer for boating and fishing.

No, the boom is still in place.

We monitor the lake closely at work and it was 95% ice covered this year. Some of it was 2 feet thick (not including piling and ice ridging).

It is still largely ice filled from Cleveland, east all the way to this end, this week.

There have been other years like this, the most memorable one was the winter of 76/77.

This volume of ice in the east end will keep this area cooler than neighboring regions for a couple weeks, yet.

 

[royce]

Guess I am confused. Not noticed a bit of excess heat from my bike (the ST), even on the trip to Salem last July. It gets plenty hot here in Kansas and all the neighboring states. Maybe it's unique to the GT???

 

[racer7]

To understand the problem on the GT, look at a side photo of the bike and look for the eyebrow shape vent near the riders knee. At speed, a steady stream of hot air exits there and gets dumped into the riders crotch by the bikes airflow pattern.
Not even the least bit pleasant.

This is either a bike that didn't get any proper hot weather development testing or where BMW simply ignored test rider comments, perhaps for some reason like "we already made the mold for the side panels"...In hot weather this issue can't be missed by any living human so whatever the answer is as to why it wasn't addressed, it doesn't speak at all well for the guys who allowed this to be sold here. Its probably a fine bike in Europe - Madrid being about the same latitude as NYC and most of it being a good deal cooler than most of the southern part of the US.

 

[racer7]

I've blocked off the two eyebrow vents with closed cell foam but so far only been able to test in 70 degree weather.
Blocking the vents does kill the two hair dryers.

What is does not do is significantly change other heat wafting off the motor so there is still a residual hot crotch issue, just without the direct hot air blast.

My wedge 06 K1200GT (though it has a mess of other engineering screwups fixed in subsequent years) apparently got development attention re heat control- for example, it has two foam blocks under the fairing that apparently serve no purpose other than directing hot air so it doesn't hit the rider. And despite the fact that its a much bigger water cooled motor, it puts a lot less heat on the rider than the little GT.
This bike is obviously a cheap out line extension product that did not get the development attention it should have re heat control.

The GT will stay parked in our hottest weather- I've got other stuff that better suits those conditions- in fact every other bike in the garage. Whether it stays in the fleet at all depends on how well it does in our mountain twisties, the reason it was purchased (and where the elevation means cooler conditions). First run this year next week.